cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A341616 Table read by ascending antidiagonals: T(n,j) = Fibonacci(n)*Lucas(n+j), product of the n-th term in the Fibonacci sequence (with F(1)=1 and F(2)=1) and the (n+j)-th term in the Lucas sequence (with L(1)=1 and L(2)=3 and j=0,1,2,...).

Original entry on oeis.org

1, 3, 3, 8, 4, 4, 21, 14, 7, 7, 55, 33, 22, 11, 11, 144, 90, 54, 36, 18, 18, 377, 232, 145, 87, 58, 29, 29, 987, 611, 376, 235, 141, 94, 47, 47, 2584, 1596, 988, 608, 380, 228, 152, 76, 76, 6765, 4182, 2583, 1599, 984, 615, 369, 246, 123, 123
Offset: 1

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Author

Jens Rasmussen, Feb 16 2021

Keywords

Comments

j is the offset when combining terms from the two initial sequences.

Examples

			T(4,3) = Fibonacci(4)*Lucas(4+3) = 3*29 = 87.
Square array showing T(n,j) begins:
      j=0 j=1 j=2 j=3 j=4  ..
  n=1   1   3   4   7  11  ..
  n=2   3   4   7  11  18  ..
  n=3   8  14  22  36  58  ..
  n=4  21  33  54  87 141  ..
  ...  ..  ..  ..  ..  ..  ..
		

Crossrefs

For j=0 the resulting sequence is used as input in A341414.

Programs

  • PARI
    T(n,j) = fibonacci(2*n+j) - (-1)^n*fibonacci(j);
    matrix(7,7,n,k, T(n,k-1)) \\ Michel Marcus, Mar 02 2021

Formula

For phi=(1+sqrt(5))/2 and tau=(1-sqrt(5))/2:
T(n,j) = Fibonacci(n)*Lucas(n+j).
T(n,j) = (phi^n - tau^n)*(phi^(n+j) + tau^(n+j))/sqrt(5).
T(n,j) = Fibonacci(2n+j) - (-1)^n*Fibonacci(j).
Lim_{n, j -> oo} T(n+1,j)/T(n,j) = phi^2 (A104457).
Lim_{n, j -> oo} T(n,j+1)/T(n,j) = phi (A001622).
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